Need input - wiring new starter

[MaineVette]

Hey guys, hoping someone can give me a bit of insight with respect to wiring in my new high torque mini starter. My old starter was wired with the following 5 wires:

Large (+) terminal - black 2 ga wire from battery and red 12 ga wire to power the rest of the car
Large (-) terminal - black 2 ga ground wire
Small side terminal (S terminal on wiring schematic) - purple 12 ga wire - starter signal
Small side terminal (R terminal on wiring schematic) - yellow 20 ga wire - power to coil

Most of the wiring for the new starter is straightforward. However, I'm trying to figure out what to do with the yellow wire which doesn't have a home on the new starter.

As I understand it the yellow wire temporarily carries a full 12 volts to the ignition coil during cranking to facilitate easy starting. Once the car was started the coil is fed by other means and receives less voltage in order to extend the life of the coil. I presume the starter solenoid was set up to feed the yellow wire only when a signal was received from the purple wire.

I'm curious how others with a similar setup have addressed this. I suspect that, with my new MSD 6AL ignition and MSD Pro-Billet distributor (part #8572), this yellow wire is no longer relevant and can simply be cut short and abandoned.

What do you guys think?

[vito]

Tim,

If I remember correctly, you don't use either original wire that goes to the + side of the coil. The MSD gets separate power and has its own harness for the coil and distributor. You can use the ACC terminal on the fuse block for keyed power to the MSD.

Also make sure you get/use the right grade bolts for the starter.

[rbryce1]

You are correct, the yellow wire goes to the "S" (Start) connection on the starter. This was because, on the older Vettes, they had "point" type ignition systems, which required 9 volts to run the car. 12 volts would rapidly burn out the contacts on the points.

The yellow wire, when the key was in the Start position, provided temporary 12 volts to the coil for starting the engine, then when the key was returned to Run, the 12 volts went away and the 9 volts continued to run the engine. The way this worked was dependent on the year of your car.

Older engines, like my '65, had 12 volts coming from the ignition switch to a ballast resistor mounted on the firewall which reduced the voltage down to 9 volts, which went to the coil. Later, as with my '68, the ballast resistor, which was not that inexpensive, was replaced with a very inexpensive resistor wire that originated at the firewall electrical block.

So 12 volts went from the ignition switch to the firewall block, then from the firewall block to the coil was a resistor wire to drop the voltage. You could not reduce the length of the wire as this would increase the voltage proportionally and I found you could not with much success solder a standard wire to it due to the type of metal used in the resistor wire. (Ask me how I know ). Also, I'm pretty sure the resistor wire was a solid wire, not strand wire, which made using a crimp connector extremely difficult, as the connector would not hold the solid wire at all.

When the High Energy Ignition System (HEI) came out, the power module in the HEI required a full 12 volts, and the resistor wire went away. In fact, if the distributor did not have a full and solid 12 volts at all times, you would burn up the power module in the HEI distributor.

It is very important to determine which ignition system you have AND what wiring is in your car.

If you need 9 volts and have the resistor wire, you will most likely be fine with just eliminating the wire. Most all engines I have had started fine on 9 volts, except in very cold weather, which made them harder to start due to a weaker spark and the cold air and fuel temperatures.

In my case, my '65 is running a wiring harness that used the ballast resistor with a HEI distributor. I removed the connectors to the ballast resistor and soldered them together with shrink tubing to provide the 12 volts to the distributor. Then I unwrapped the tape on the harness and removed the wire that went from the starter to the coil and re-wrapped the harness. You could cut the connection and cap it with shrink tubing or just tape over the connector as well.

On my '68, I bought the spade plug that goes into the firewall connector and replaced the entire wire with a standard 16 gauge wire to the distributor to get the 12 volts to the HEI. I have some extra connectors if you need some.

Again, it is most important to determine what voltage your ignition system requires AND what type of wiring is in your harness. Either way, you most likely don't need the wire from the starter to the coil, especially where you live.

[vito]

Ya know I was thinking Bob, that resistor wire is about two feet-ish in length. you could cut it where it is spliced and use that wire for power.

I can take a picture if it helps.

[rbryce1]

Ya know I was thinking Bob, that resistor wire is about two feet-ish in length. you could cut it where it is spliced and use that wire for power.

I can take a picture if it helps.

Not sure what you are describing, but if you are talking about cutting off the resistor wire and running a strand wire to the ignition system, I don't believe you will have a lot of luck with that. I edited my last post about this. I could not get a wire connector to crimp onto the resistor wire and hold for long, as the solid wire will not crimp like the strand wire does. I didn't have shrink tubing available back then, that may help. I could not solder the two wires either. The resistor wire would not hold the solder.

Ultimately, I replaced the spade connector in the firewall harness and attached a strand wire to the new spade connector. If this is what you are talking about, I can give you some spade connectors. If not, maybe you could post a photo like you said.

[vito]

Your correct Bob,

Since I am waiting for paint to dry I checked my harness. The entire wire length is resistive. NO splices. It has an ohm reading of 1.6. Also note that the wire is a 7 strand type.

Where did you get your fuse box/harness connectors?

[rbryce1]

It was quite a while ago, but I think I got them here.

http://texasindustrialelectric.com/_pac ... minals.asp

I'm not 100% positive though. If you need some I have plenty of spares, as I bought a quantity, then realized I could not build my own complete harness because no one would sell the fuse box separately.

[MaineVette]

Hey guys, just a quick update. I have the starter all wired up after a bit of trial and error. Some Bubba that came before me thought it would be a good idea to splice in a section of red wire in place of the original purple wire which carries the starter wire. That one had me scratching my head for a bit.

I've reviewed the wiring diagram for both my ignition box (MSD 6AL) as well as my MSD distributor (non-HEI). Based on those it doesn't appear there's any need for a resistor wire so I'm abandoning them.

I'm grounding the MSD box to the frame and pulling power via the heavy red wire from the starter terminal. The orange and black wires from the ignition box go to the + and - coil terminals respectively. Lastly, the small red wire is connected into the fuse box to pull power from a keyed power source. With this setup I'm able to crank the engine using the key. I also verified I'm getting spark from the distributor. Awesome and really not that difficult. I'm going to abandon the original ignition coil wires since I don't need them. That said, I'm just going to tuck them out of sight until I get all the wrinkles ironed out.